private void RunUpdates()

in src/ICSharpCode.SharpZipLib/Zip/ZipFile.cs [3012:3162]
128 lines of code
27 McCabe index (conditional complexity)

		private void RunUpdates()
		{
			long sizeEntries = 0;
			long endOfStream = 0;
			bool directUpdate = false;
			long destinationPosition = 0; // NOT SFX friendly

			ZipFile workFile;

			if (IsNewArchive)
			{
				workFile = this;
				workFile.baseStream_.Position = 0;
				directUpdate = true;
			}
			else if (archiveStorage_.UpdateMode == FileUpdateMode.Direct)
			{
				workFile = this;
				workFile.baseStream_.Position = 0;
				directUpdate = true;

				// Sort the updates by offset within copies/modifies, then adds.
				// This ensures that data required by copies will not be overwritten.
				updates_.Sort(new UpdateComparer());
			}
			else
			{
				workFile = ZipFile.Create(archiveStorage_.GetTemporaryOutput());
				workFile.UseZip64 = UseZip64;

				if (key != null)
				{
					workFile.key = (byte[])key.Clone();
				}
			}

			try
			{
				foreach (ZipUpdate update in updates_)
				{
					if (update != null)
					{
						switch (update.Command)
						{
							case UpdateCommand.Copy:
								if (directUpdate)
								{
									CopyEntryDirect(workFile, update, ref destinationPosition);
								}
								else
								{
									CopyEntry(workFile, update);
								}
								break;

							case UpdateCommand.Modify:
								// TODO: Direct modifying of an entry will take some legwork.
								ModifyEntry(workFile, update);
								break;

							case UpdateCommand.Add:
								if (!IsNewArchive && directUpdate)
								{
									workFile.baseStream_.Position = destinationPosition;
								}

								AddEntry(workFile, update);

								if (directUpdate)
								{
									destinationPosition = workFile.baseStream_.Position;
								}
								break;
						}
					}
				}

				if (!IsNewArchive && directUpdate)
				{
					workFile.baseStream_.Position = destinationPosition;
				}

				long centralDirOffset = workFile.baseStream_.Position;

				foreach (ZipUpdate update in updates_)
				{
					if (update != null)
					{
						sizeEntries += workFile.WriteCentralDirectoryHeader(update.OutEntry);
					}
				}

				byte[] theComment = newComment_?.RawComment ?? _stringCodec.ZipArchiveCommentEncoding.GetBytes(comment_);
				ZipFormat.WriteEndOfCentralDirectory(workFile.baseStream_, updateCount_, 
					sizeEntries, centralDirOffset, theComment);

				endOfStream = workFile.baseStream_.Position;

				// And now patch entries...
				foreach (ZipUpdate update in updates_)
				{
					if (update != null)
					{
						// If the size of the entry is zero leave the crc as 0 as well.
						// The calculated crc will be all bits on...
						if ((update.CrcPatchOffset > 0) && (update.OutEntry.CompressedSize > 0))
						{
							workFile.baseStream_.Position = update.CrcPatchOffset;
							workFile.WriteLEInt((int)update.OutEntry.Crc);
						}

						if (update.SizePatchOffset > 0)
						{
							workFile.baseStream_.Position = update.SizePatchOffset;
							if (update.OutEntry.LocalHeaderRequiresZip64)
							{
								workFile.WriteLeLong(update.OutEntry.Size);
								workFile.WriteLeLong(update.OutEntry.CompressedSize);
							}
							else
							{
								workFile.WriteLEInt((int)update.OutEntry.CompressedSize);
								workFile.WriteLEInt((int)update.OutEntry.Size);
							}
						}
					}
				}
			}
			catch
			{
				workFile.Close();
				if (!directUpdate && (workFile.Name != null))
				{
					File.Delete(workFile.Name);
				}
				throw;
			}

			if (directUpdate)
			{
				workFile.baseStream_.SetLength(endOfStream);
				workFile.baseStream_.Flush();
				isNewArchive_ = false;
				ReadEntries();
			}
			else
			{
				baseStream_.Dispose();
				Reopen(archiveStorage_.ConvertTemporaryToFinal());
			}
		}